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Understanding the photoluminescence behaviour in nano CaZrO3:Eu3+ pigments by Judd-Ofelt intensity parameters

Kumar, S G Prasanna and Krishna, R Hari and Kottam, Nagaraju and Murthy, P Krishna and Manjunatha, C and Preetham, R and Shivakumara, C and Thomas, Tiju (2018) Understanding the photoluminescence behaviour in nano CaZrO3:Eu3+ pigments by Judd-Ofelt intensity parameters. In: DYES AND PIGMENTS, 150 . pp. 306-314.

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Official URL: http://dx.doi.org/10.1016/j.dyepig.2017.12.022

Abstract

CaZrO3 ceramic pigment exhibits high chemical, thermal and structural stability. However, its application as a host for various luminophores/activators has not been clearly explored. In the present investigation, CaZrO3 doped with Eu3+, as a potential orange-red phosphor has been demonstrated. Ca1-xZrO3:Eu-x (x = 0.01-0.09) nanophosphor is prepared here through a low temperature, one pot solution combustion synthesis approach using glycine as the fuel. X-ray diffraction results show that all the samples are stabilized in orthorhombic crystal structure without any impurity phases. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution TEM are carried out to determine the microstructure of the phosphor. The particles are found to be significantly agglomerated and in the nano-regime (similar to 40 nm). The observed excitation spectrum suggests that Ca1-xEuZrO3 can be efficiently excited using ultra-violet (UV), near-UV and UV blue (UVB), making it immediately relevant for current solid state lighting technologies. In fact with every similar to 1 at% doping increase, the primary excitation line intensity increases by a factor of similar to 1.5; this provides a simple parameter to enhance the UV excitability of the phosphor. The color coordinates are deduced using the Commission International De Eclairage (CIE) co-ordinates (x, y = 0.58, 0.40). The critical distance of energy transfer in this system is determined to be similar to 10.7 angstrom, making multipole-multipole interactions as the plausible reason for concentration quenching beyond 7 mol.% Eu doping. The luminescence behaviour of the material is evaluated using Judd-Offelt (JO) intensity parameters. Judd-Ofelt (JO) intensity parameters (Omega(2) and Omega(4)) are calculated for the sample Ca1-xZrO3:Eu-x (x = 0.01-0.09), in order to understand the local structure around the activator. Irrespective of the concentration of Eu3+, Omega(2) is found to be greater than Omega(4), indicating asymmetric environment around the activator. Furthermore, with increase in Eu3+, Omega(2) increases suggesting an increase in covalency of Eu-O bonds with significant effect of host crystal field on Eu3+.

Item Type: Journal Article
Additional Information: Copy right for the article belong to ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Depositing User: Id for Latest eprints
Date Deposited: 02 Apr 2018 19:57
Last Modified: 02 Apr 2018 19:57
URI: http://eprints.iisc.ac.in/id/eprint/59452

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